Forming apparatus



Feb, 14-, 1939. A. 5 1455 2,146,823

FORMING APPARATUS Filed Jline 2'7, 1956 A5. L/SS BY ATTOR/Vf) Patented Feb. 14, 1939 UNITED STATES PATENT OFFICE 2,146,828 I FORMING APPARATUS Application June 27,

5 Claims.

This invention relates to forming apparatus, and more particularlyto a punch and die for forming sheet metal articles.

The invention is particularly applicable to ap- 5 paratus for forming from sheet metal, telephone pay station housings of the type disclosed in a copending application of R. Polivka and R. C. Wendell, Serial No. 657,184, filed February 17, 1933, Patent Number 2,060,893. Such housings comprise parallel side wall portions interconnected by top and front Wall portions, the front and side wall portions having a continuous outwardly directed flange along their bottom edges.

An object of the present invention is to provide apparatus capable of expeditiously and economically forming articles of the aforementioned type.

In accordance with one embodiment of the invention, a forming punch and die structure for forming such housings is provided in which the punch comprises two forming members movable one with respect to the other in the direction of the forming stroke of the punch. Means is provided for positively constraining said members to move as a unit during an initial portion of the operating stroke of the punch to partially form the housing, whereupon the constraining means is automatically rendered ineffective, thereby permitting relative motion of the forming members to complete the forming operation during the final portion of the operating stroke of the punch.

Other features and advantages of the invention will become apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawing, in which Fig. 1 is a vertical sectional view of a punch and die structure embodying the features of the invention, shown associated with a conventional punch press, a portion of which is illustrated;

Fig. 2 is a cross-sectional view taken on the line 2-2 of Fig. 1;

Fig. 3'is a vertical sectional view similar to Fig. 1, but with the collapsible forming member of the punch shown in the collapsed position;

Fig. 4 is a plan view of a partially formed sheet metal blank adapted to be further formed into a telephone pay station housing by the forming punch and die shown in Figs. 1 to 3, inclusive, and

Fig. 5 is a perspective View of a completely formed housing,

Referring now to the drawing, a preferred embodiment of the invention is illustrated in Figs. 1 to 3, inclusive, and comprises a forming punch I and a cooperating die l'l adapted to form a telephone pay station housing l2 (Fig. from a 1936, Serial No. 87,680

sheet metal blank l3 (Fig. 4). The blank 13 comprises a central portion [4 to form the front wall of the housing, two side portions l5 and I6 for the side walls of the housing, and a top portion I! for the top of the housing. The front wall portion M has a circular perforation I 8 for accommodating a telephone dial (not shown). Outwardly directed flanges I9, and 2! are formed along the bottom edges of the front and side wall portions [4, i5 and I6, respectively, the flanges being separated by reversely bent portions 22, 22 at the junctions of the front wall portion with the side wall portions.

The forming punch and die herein illustrated and described as representative of one embodiment of the invention is adapted to completely form the housing I2 from the blank l3 by folding the top and side wall portions of the blank along the broken lines shown in Fig. 4 and forming the reversely bent portions 22 of the blank into corner flanges 23, 23 (Fig. 5), interconnecting the flanges I9, 20 and 2| and constituting therewith a continuous uniform flange along the bottom of the housing.

The forming punch is adapted to be attached to a movable platen or ram 25 of a conventional punch press, of which only a portion of the ram is illustrated. The punch comprises a main body portion 26 of substantially inverted channel crosssection, having an end flange-forming member 21 rigidly attached to one end thereof and a cover plate 28 fixed to its opposite end. A second forming member or collapsible face plate 30 is mounted for vertical movement with respect to forming member 21 by being suspended from the body portion 26 by means of a plurality of vertically slidable rods 3|, the lower ends of which are threaded into the face plate. The rods have enlarged heads 32 at their upper ends for limiting downward movement of face plate 3|] with respect to forming member 21.

The bottom and side edges of forming member 21 extend beyond the boundaries of body portion 26 and are formed to provide a continuous flange forming surface 33 corresponding to the continuous flange on the bottom of the housing shown in Fig. 3.

In Fig. 1 the face plate is shown in its normal or expanded position, i. e. in its lowermost position with respect to the flange forming member 21. In this position of the face plate its bottom surface is approximately flush with or slightly below the lowermost surface of the flange forming member 21. When forming pressure is initially applied this relationship between the face plate and the flange forming member is maintained by a filler block 40 longitudinally slidable between the face plate and a liner plate 34 attached to the bottom of the channel in the body portion 26. A pair of transverse rollers 42 are mounted in retaining grooves 43 in the top surface of the filler block and a similar pair of rollers are similarly mounted in the bottom surface of the filler block. The upper rollers project above the top surface of the filler block and the lower rollers project below the bottom surface of the filler block.

In the expanded position of the face plate the projecting portions of the upper rollers separate the top surface of filler block 40 from liner plate 34, and the projecting portions of the lowerrrollers separate the face plate from the bottom surface of the filler block. A coil spring 45 normally serves to yieldably hold the filler block in the position in which it is shown in Fig. 1.

For cooperating with the punch H), the die I I is provided, which is of conventional construction, having a die cavity 41 shaped to conform to the article to be produced. The die is adapted to be attached to the stationary platen or bed of the press (not shown). Mounted for vertical movement within the die cavity is a yieldable pad 46 carried by a plurality of vertically reciprocable rods 48 yieldably pressed upward by springs or other suitable means in a manner well known in the art. The top surface of the pad conforms in dimensions and contour to the front wall portion of the housing to be formed and is normally flush with the top edge of the die cavity.

A vertical pin 50 is attached to a stationary portion of the die and extends upwardly through a circular perforation 5| in pressure pad 46. The upper end of the cam pin projects above the pressure pad and as the punch moves downwardly is adapted to extend through a circular perforation 52 in face plate 30 and into a bifurcation 53 in filler block 40. Upon entering the bifurcation the cam pin shifts the filler block, to the left through the sliding action of cooperating tapered cam surfaces 54 and 55 of the cam pin and filler block. Before the punch reaches the end of its downward movement into the die the filler block is shifted by the cam pin. to a position in which the upper spacing rollers 42 are in alignment with transverse notches 56 in liner plate 34 and the lower spacing rollers are in alignment with similar notches in face plate 30. As soon as the filler block arrives at this position the spacing rollers are forced to enter the respective notches 56 under the upward pressure of pressure pad 46 and by the continued downward movement of the press ram. The face plate 30 is thereby collapsed to the position shown in Fig. 3, thus permitting the flange forming member 2'! to move downwardly with respect to the face plate.

In the operation of the apparatus a blank I3 is positioned on the die so that the cam pin 50v projects through the perforation l8 and the front wall portion I4 of the blank coincides with the pressure pad 46, the top wall portion of the blank extending beyond the right hand edge of the pressure pad. The press is then operated to move the forming punch downwardly. The blank is first engaged by the face plate 30 which, in cooperation with the die, bends up the top and side wall portions of the blank as the punch continues its downward movement, the pressure pad meanwhile being pressed downwardly During this portion of the forming operation the face plate 30 is rigidly held in its expanded position by the filler block 40 which maintains the bottom flange forming surface of forming member 21 slightly above the blank. Upon the completion of the bending of the top and side wall portions and during the continued downward movement of the press ram the face plate 30 is automatically collapsed in the manner above described, thereby causing the flange forming member 21 to move downwardly with respect to the face plate and form the reversely bent portions 22 of the blank into the corner flanges 23, thus completing the forming operation. As the punch is withdrawn the face plate is restored to its expanded position under its own weight and the weight of the filler block aided by the pressure of coil spring 45 which restores the filler block to its normal position and further aided, if necessary, by coil springs 60 interposed between the face plate and the filler block.

From the above description it will be obvious that by the use of forming apparatus embodying the invention, sheet metal articles requiring successive bending or forming operations may be produced by a single punch press operation. It should be understood, of course, that the embodiment of the invention herein described is merely illustrative of a practical application of the invention, which is not limited to the particular construction and combination of elements disclosed, except as defined by the appended claims.

What is claimed is:

1. In a forming apparatus, a forming element comprising two members, one of which is movable with respect to the other, a filler block slidable between said members and capable of assuming two positions, in one of which said filler block is effective for preventing relative movement between said members, and a projection on said filler block in movable engagement with a surface of one of said members, said surface having a notch for receiving said projection upon movement of the filler block to the other position,

to thereby permit a. relative movement of one of said members with respect to the other.

2. In a forming apparatus, a forming element comprising two members, one of which is movable with respect to the other, a filler block slidablebetween said members and capable of assuming two positions, in one of which said filler block is effective for preventing relative movement between said members, and a roller mounted in and having a portion projecting from a surface of said filler block and in rolling engagement with a surface of one of said members, the said surface of the member having a notch for receiving the projecting portion of said roller upon movement of the filler block to the other position, to thereby permit a relative movement of one of said members with respect to the other.

3. In a forming apparatus, a forming element comprising two members, one of which is movable with respect to the other, a filler block slidable between said members and capable of assuming two positions, in one of which said filler block is effective for preventing relative movement between said members, rollers mounted in and having portions projecting from opposite sides of said filler block and in rolling engagement with adjacent surfaces of saidmembers, respectively, the said surfaces of said members having notches for receiving said projecting portions of the rollers, respectively, upon movement of the filler block to the other position, to thereby permit a relative movement of one of said members with respect to the other.

4. In a forming apparatus, a forming element comprising two members movable in one direction, one of which is movable in said direction with respect to the other, movable constraining means capable of assuming'two positions between said members and effective in one of said positions for constraining the members to move as a unit in said direction, said constraining means having a projection in movable engagement with a surface of one of said members, said surface having a notch for receiving said projection upon movement of the constraining means to the other position to thereby permit a relative movement of one of said members with respect to the other, means for holding the constraining means in the effective position, and means responsive to a predetermined unitary movement of said members for moving the constraining means to the other Position.

5. In a forming apparatus, a forming die, a forming punch movable with respect thereto for cooperating therewith to form an article, said forming punch comprising two members movable in the' same direction, one of which is movable in said direction with respect to the other, a filler block slidable to two positions between said members and effective in one of said positions for constraining said members to move a unit in said direction, a projection on said filler block in rolling engagement with a surface of one of said members, said surface having a notch for receiving said projection upon movement of the filler block to the other position to thereby permit a relative movement of one of said members with respect to the other, a spring for holding the filler block in the effective position, and cam means responsive to a relative movement of the forming punch with respect to the forming die for moving the filler block to the other position.

AUGUST S. LISS. 

